The present invention relates to low voltage swing sense amplifiers and method for making the same in the presence of expected manufacturing errors inherent in the manufacturing of the sense amplifiers as integrated circuits.
Low voltage swing sense amplifiers are known. Typically, they generate valid output data signals in the presence of a relatively small potential difference between two input data signals. Whereas "full rail circuits" do not generate data outputs until an input data signal undergoes a large voltage swing (typically &gt;1 volt), the low voltage swing sense amplifier can generate valid outputs in the presence of a potential difference of only a few hundred millivolts. This difference in operation can cause a low voltage swing sense amplifier to operate at a much higher frequency than the full rail circuit.
Often, when designing a logic circuit for use in integrated circuits, a circuit designer must account for manufacturing errors that necessarily will be introduced when the circuit is fabricated. Typically, the design process requires an iterative circuit simulation process in which the designer is advised of statistical manufacturing variations that likely will occur for selected components. The circuit designer then runs repeated circuit simulations to determine whether the logic circuit will operate as intended if the expected manufacturing variations occur. Results of the circuit simulations may require that circuit components be resized. The circuit simulations typically are concluded when a logic circuit design is obtained that operates correctly in view of the expected manufacturing variations.
Low voltage swing sense amplifiers are subject to stringent manufacturing tolerances that may not be important other circuit architectures, such as full rail circuits. As explained below, strict sizing relationships must be maintained between various components of a low voltage swing sense amplifier. The iterative circuit simulation process described above can be expected to be particularly tedious because of the strict manufacturing tolerances required for the circuit.
There is a need in the art for a low voltage swing sense amplifier having a robust design that is less susceptible to manufacturing errors that can be expected during fabrication. Further there is a need in the art for a method of selecting components of a low voltage swing sense amplifier that avoids the tedious circuit simulation process that is typical of logic circuits.